Limiting shapes of confined lipid vesicles.

We theoretically study the shapes of lipid vesicles confined to a spherical cavity, elaborating a framework based on the so-called limiting shapes constructed from geometrically simple structural elements such as double-membrane walls and edges. Partly inspired by numerical results, the proposed non-compartmentalized and compartmentalized limiting shapes are arranged in the bilayer-couple phase diagram which is then compared to its free-vesicle counterpart. We also compute the area-difference-elasticity phase diagram of the limiting shapes and we use it to interpret shape transitions experimentally observed in vesicles confined within another vesicle. The limiting-shape framework may be generalized to theoretically investigate the structure of certain cell organelles such as the mitochondrion.

A four-year follow-up of duodenal ulcer patients after Helicobacter pylori eradication.

BACKGROUND/AIMS: The aim of our study was to evaluate the clinical course of disease in 63 duodenal ulcer (DU) patients during a 4-year follow-up after Helicobacter pylori (H. pylori) eradication. METHODOLOGY: Upper gastrointestinal endoscopy and a clinical interview were performed before antimicrobial therapy, 2 months after, yearly and when symptoms recurred. Two antral and two corporal specimens were taken for histology, and one additional specimen from antrum was taken for rapid urease test at the first endoscopy and for culture at the following endoscopies. All patients received triple antimicrobial regimens based on colloidal bismuth subcitrate, amoxycillin and metronidazole for at least 2 weeks. Patients with a negative histology and culture 2 months after antimicrobial therapy were included in the study. RESULTS: After H. pylori eradication, ulcer recurrence dropped from 84.1% per year in the year before H. pylori eradication to a mean value of 5.2% per year during 2076 patient months (p<0.01). The increased incidence of gastroesophageal reflux disease (GERD) was found only in the first year of the follow-up period. The average percentage of anti-ulcer drug users per year was 30.8% because of GERD, reflux symptoms, ulcer recurrence or non-ulcer dyspepsia. Ulcers or acute erosions recurred in 9 H. pylori-negative patients; recurrences were attributable to non-steroidal anti-inflammatory drugs (NSAID) in 4 out of 9 cases (44.4%). CONCLUSIONS: H. pylori eradication changed the long-term course of DU disease.

Two- to four-year histological follow-up of gastric mucosa after Helicobacter pylori eradication.

In a 2- to 4-year prospective study, the reversibility of gastritis after Helicobacter pylori eradication was analysed. Sixty-three H. pylori-positive, chronic duodenal ulcer patients were studied after the successful eradication of bacteria in the period from 1990 to 1993. H. pylori eradication was obtained by triple antimicrobial regimens (colloidal bismuth subcitrate, amoxycillin, and metronidazole) applied for at least 14 days. The criteria for eradication were the absence of bacteria from two antral and two body of stomach biopsies stained with haematoxylin, eosin, and Warthin Starry, and a negative antral biopsy culture. The same diagnostic procedures were repeated, at regular follow-up endoscopies, each year for up to 4 years. Neutrophil-granulocyte infiltration of gastric mucosa disappeared in 2 months after bacterial eradication. Mononuclear cellular infiltration was disappearing with statistical significance up to the second year and normal mucosa was observed in the majority of patients in the fourth year of follow-up. Degeneratively changed lymphoid aggregates were also present in the fourth year in the antrum (12.5 per cent of patients) and in the body of stomach (14 per cent of patients). There was no significant change in antral intestinal metaplasia during the 4 years of follow-up. Antral atrophy declined significantly in the period from 1 to 3 years of follow-up. In conclusion, 3-4 years are needed for gastric mucosa to become normal after H. pylori eradication, although some residual lymphoid aggregates persist even after that period.

Interobserver agreement in the assessment of gastritis reversibility after Helicobacter pylori eradication.

AIM: Our aim was to determine interobserver agreement in the application of the Sydney system to assess reversibility of gastritis after Helicobacter pylori eradication. METHODS AND RESULTS: Forty-three patients with a Helicobacter pylori-positive duodenal ulcer disease were included in the study. All patients included had successful H. pylori eradication after different antimicrobial drug combinations. Biopsy samples were collected from antrum and body, according to the Sydney recommendations, before antimicrobial therapy, 2 months after and at yearly intervals during 2-4 years of follow up. Three pathologists, who were blind to clinical data, evaluated histological changes in 221 antral and 219 body specimens stained with haematoxylin and eosin and with Warthin Starry. The percentage of pairwise agreement, kappa and weighted kappa statistic were used. Agreement in recognizing the presence of H. pylori colonization of the gastric mucosa, activity of inflammation and intestinal metaplasia was over 90%. Agreement in recognizing chronic inflammation in the body and atrophy in the antrum was between 78 and 89% respectively. The kappa values were excellent (more than 0.75) for the grade of H. pylori in the body, good (between 0.50 and 0.75) for the grade of H. pylori in the antrum, grade of inflammatory activity and intestinal metaplasia in the antrum and moderate to good (0.38-0.53) for the grade of chronic inflammation. Kappa values were poor to good (from 0.17 to 0.57) only in evaluation of the grade of atrophy. CONCLUSION: Interobserver agreement in the application of the Sydney system to reversibility of gastritis after H. pylori was good. More strict criteria should be used for atrophy and to differentiate normal and mild chronic inflammation.